In a known unit of the type described above, the sharp change in the feed direction of the filter portions sometimes results in jams, the frequency of which is in direct proportion to the operating capacity of the filter assembly machine connected to the unit. Jams of this sort must obviously be cleared immediately, by not only blocking the filter feed unit, but also, in a relatively short space of time, the filter assembly machine connected to the unit.
On the other hand, known units of the type described are normally so complex in design as to make fast manual intervention by an operator from the outside difficult, so that jamming invariably involves considerable downtime and, very often, stoppage of the relative filter assembly machines.